1. Field of the Invention
The present invention relates to a molding attached to the circumference of an upper frame of an automobile above a door of the automobile, and more particularly to an integrated molding and a manufacturing method thereof, into which separated conventional molding pieces manufactured hitherto in various ways such as roll forming and insert molding are incorporated, and which is integrally manufactured in a unified single manufacturing way including the insert-injection molding.
2. Description of the Prior Art
A molding disposed at a side portion of an automobile above a side door of the automobile is a part which closes clearance between the side door and frame of the automobile, thereby preventing introduction of water and wind noise and providing the automobile with an external appearance of a higher class. The molding of the automobile as described above includes a drip rail molding 1 and a rear piece drip rail molding 2, which are separately manufactured and assembled with each other to be attached to the automobile.
The process of manufacturing the drip rail molding 1 includes 27 steps, which will be briefly described hereinafter (see FIGS. 2 and 3).
That is, the drip rail molding 1 is manufactured through the steps of: applying adhesive to one surface of a stainless coil 3 so as to facilitate attachment of polyvinyl chloride (PVC); drying; roll-forming the stainless coil 3 into a desired shape through twelve steps; extruding the PVC 4 onto the molding surface of the roll-formed stainless coil 3; cooling; cutting the coil with the PVC into moldings with a regular length; stretch-bending the molding according to the side frame shape of the vehicle frame so that the molding can be attached to the vehicle frame; pressing (including the steps of cutting the end of the front surface, chamfering the end, notching, and cutting the end of the rear surface); cutting the end portion, which is assembled with the rear piece drip rail molding, by means of a high-speed saw; applying adhesive to the injection portion so as to finish the end of the molding disposed at the front side of the automobile; insert-injection molding the PVC 4 onto the injected end portion of the molding; and assembling a clip 5, which is assembled with the vehicle frame, on the inner surface of the drip rail molding 1 (in this case, the clip is separately manufactured and processed from the injection molding, and then is assembled with the drip rail molding).
In order to assemble the drip rail molding manufactured in the way described above with the vehicle frame 6, a separate drip rail 7 is manufactured and fixed to the vehicle frame by means of spot welding and so on. In this case, the conventional drip rail molding 1 is manufactured through roll forming and extrusion, the drip rail 7 is necessary for the assembling of the drip rail molding and the process of manufacturing the drip rail is included in the process of manufacturing the vehicle frame.
Further, the process of manufacturing the rear piece drip rail molding 2 includes 21 steps, which will be briefly described hereinafter (see FIGS. 4 and 5).
That is, the rear piece drip rail molding 2 is manufactured through the steps of: pressing a stainless coil 8 into a molding shape; attaching protective tape onto the molding surface of the stainless coil 8 (so as to prevent the surface from being scratched while being carried); removing the protective tape and ultrasonic-cleaning the molding surface; drying; applying adhesive to the molding surface in order to facilitate attachment to the stainless coil 8 when injection molding the PVC 9; drying; secondarily applying an adhesive in order to reinforce the attachment force; drying; high-frequency preheating the adhesive by a high-frequency pre-heater; injection molding the PVC 9 onto the molding surface; eliminating unnecessary injection gate and finishing; attaching protective tape; assembling a clip 10 by means of an assembling jig; and spot-welding the joint portion so that the rear piece drip rail molding is aligned with the drip rail molding when it has been assembled.
The rear piece drip rail molding manufactured in the way described above is assembled with the vehicle frame by inserting the clip 10 fixed to the inner surface of the rear piece drip rail molding 2 into an assembling hole formed in advance through the vehicle frame 6.
As described above, the conventional molding for a side door of an automobile includes two separated moldings which are manufactured through complicated method including two different ways of molding, insert-press molding and roll forming molding. Therefore, not only the manufacturing cost is increased, but also wind noise may be generated and the external appearance of the automobile may deteriorate due to a possible gap between the moldings. Moreover, there is a high possibility that alien material is caught in the gap when the automobile is washed (especially by an automatic car-wash machine).
Further, while the drip rail molding is manufactured by roll-forming the stainless coil and protruding the PVC onto the surface of the stainless coil, the rear piece drip rail molding is manufactured by pressing the stainless coil and injection-molding the PVC onto the surface of the stainless coil. Therefore, surfaces of the two moldings may have different colors due to the difference between the ways of forming the stainless coils and the difference between the ways of processing the PVC, the protrusion and the injection-molding.
Furthermore, in order to attach the drip rail moldings to the vehicle frame, drip rails must be separately manufactured and assembled with the vehicle frame, which further complicates the process.
Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and an object of the present invention is to provide an integrated molding of an automobile and a method of manufacturing thereof, into which separated conventional molding pieces manufactured hitherto in various ways are incorporated, and which is integrally manufactured using a unified single manufacturing procedure including insert-injection molding and pressing.
In order to accomplish this object, there is provided a method of manufacturing an integrated molding which is attached to a portion of a vehicle frame above a door of an automobile, the method comprising the steps of: pressing a stainless coil into an integrated coil body having a desired shape corresponding to the integrated molding, the stainless coil having a first surface to which adhesive is applied and a second surface to which protective tape is attached; slightly bending both ends of the integrated coil body; performing a first insert injection molding so as to form a propylene resin body attached to an inner surface of the stainless coil through, the propylene resin body including a first propylene resin layer and a plurality of clips formed integrally with the first propylene resin layer; performing a second insert injection molding so as to form polypropylene resin caps on both side edges of the integrally-attached stainless coil and first polypropylene resin layer, each of the polypropylene resin caps having a second polypropylene resin layer; subjecting the stainless coil and the first and second polypropylene resin layers, formed integrally with each other, to a finishing process, thereby producing the integrated molding; and assembling auxiliary clips, each on each of the clips.
In accordance with another aspect of the present invention, there is provided an integrated molding which is attached to a portion of a vehicle frame above a door of an automobile, the integrated molding comprising: a stainless coil having a first surface to which adhesive is applied and a second surface to which a protective tape is attached, the stainless coil being pressed into an integrated coil body having a desired shape corresponding to the integrated molding, both ends of the integrated coil body being slightly bent; a propylene resin body integrally formed on an inner surface of the stainless coil through a first insert injection molding, the propylene resin body including a propylene resin layer and a plurality of clips formed integrally with the propylene resin layer; polypropylene resin caps integrally formed on both side edges of the integrally-attached stainless coil and the first polypropylene resin layer through a second insert injection molding, each of the polypropylene resin caps having a second polypropylene resin layer, the stainless coil and the first and second polypropylene resin layers, formed integrally with each other, being subjected to a finishing process, thereby producing the integrated molding; and a plurality of auxiliary clips assembled, each on each of the clips.